Trench digging and refilling apparatus



July 25, 1967 H. E. IDOINE TRENCH DIGGING AND REFILLING APPARATUS 2 Sheets-Sheet 1 Filed Jan. 22, 1965 INVENTOR. HARRY E. /D0//VE BY MAHOA/EY, HA Laser 3 HO/QA/BAKEE ArrOQA/EYS July 25, 1967 mo 3,332,249

TRENCH DIGGING AND REFILLING APPARATUS Filed Jan. 22, 1965 2 Sheets-Sheet 2 /02 FIG. 6.

INVENTOR. 24 20 HARRY E /DO//VE BY MAHO/VE), HALBEET 8: HOEA/EAKEE United States Patent ABSTRACT OF THE DISCLOSURE An earth trenching and refilling apparatus attached to a tractor which has a vertically oriented trench digging unit continuously elevating the dirt to a circular horizontal conveyor that is reversible and from which the dirt is.

discharged rearwardly into the trench for refilling or laterally alongside the trench depending on the direction of movement of the conveyor. The apparatus is adapted to continuously feed a cable into the trench between the locations of digging and refilling the trench.

This invention relates to a trench digging device, known in the industry as a trencher and, more particularly, to a trencher equipped with a conveyor, the trencher being constructed so as to be able to dig a trench, re-fill the trench so as to cover a cable or conduit laid in the trench following the digging operation, all in one continuous operation.

Vehicle mounted trenchers of various kinds are used extensively for rapid, continuously progressive digging of trenches. Generally, these trenchers incorporate means for piling the dirt removed from a trench laterally of the trench. If the trench is to be used for underground laying of cable, flexible pipe, or the like, when a substantial section of trench has been dug, the cable or pipe must be separately laid in the trench by separate crews, and when the cable or pipe has been so positioned, the trench is generally filled by other crews, by hand-shovelling the dirt deposited alongside the trench, or by machine backfill, all at a substantial expenditure of manpower and time.

It is a primary object of the present invention to provide a trencher which will not only rapidly produce a proper trench, but will also promptly re-fill the trench over a cable or conduit laid in the trench following the digging operation, all in one continuous operation.

It is a further object of the invention to attain the primary object so rapidly that it will not be necessary to deposit the dirt removed from the trench prior to refilling, the complete operation being handled so expeditiously that the dirt is lifted from the cut, conveyed about the trencher, and discharged for refilling, all while the cable or conduit is being laid.

It is another object of the invention to provide simpli fied conveyor means which may be readily mounted on a trencher without substantial modification of the trencher itself.

It is yet another object of the invention to provide such means which will not interfere with the normal trench digging and lateral piling functions of the trencher when it is desired to use the trencher for normal trench digging operations not involving rapid laying of cable or conduit.

With these and other objects in view, the invention consists of the construction, arrangement and combination of the various elements of the device whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claims, and illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a side elevational view of the device of the present invention in operating position.

3,332,249 Patented July 25, 1967 FIgICi. 2 is a plan view of the device as illustrated in FIG. 3 is an enlarged, fragmentary plan view of the conveyor element illustrated in FIG. 2 showing details of the construction thereof.

FIG. 4 is a fragmentary side elevatioual View of the device as illustrated in FIG. 3.

FIG. 5 is an enlarged cross-sectional view taken on line 55 of FIG. 3.

FIG. 6 is an enlarged cross-sectional view taken on line 6-6 of FIG. 3.

FIG. 7 is a cross-sectional view showing an alternative form of construction of the conveyor ring element of the present invention.

As best seen in FIGS. 1 and 2 of the drawings, for ease of description and illustration, the device of the present invention is shown as applied to a wheel-type form of trencher, but it will be readily understood that the invention may be applied to other forms of trenchers, such as the ladder-type of trencher disclosed in United States Letters Patent No. 2,790,255.

As viewed in FIGS. 1 and 2, a vehicle such as a tractor 10 has a digger unit 12 mounted thereon extending beyond one end 14 of the tractor 10. An operators seat 16 is mounted on the tractor 10. Preferably, but not necessarily, the operators seat 16 is offset laterally from the tractor 10 so that the operator may have a clear view of the trenching, conduit or cable laying, and re-fill operations of the device, and so that the operator may easily watch the line and grade as the trencher progresses.

The digger unit 12 is comprised of two wheel body members 20 disposed in space relation to each other. A plurality of spaced-apart buckets 22 are transversely mounted on the wheels 20 and extend outwardly therefrom. The buckets 22 have digging teeth 24 protruding therefrom, the teeth 24 being disposed so as to dig into the earth and load the buckets 22 as the wheels are revolved in a counterclockwise direction and lowered into the earth. As the wheels 20 revolve, the buckets 22 carry the removed dirt upwardly, and then, as the buckets 22 start a downward movement, the dirt contained in the buckets 22 is discharged between the wheels 20 onto a conveyor ring, as hereinafter described in detail.

The assembly of the wheels 20 and the buckets 22 is connected to the tractor 10 and supported by a pair of articulated supporting arms 26 which are pivotally mounted on the tractor 10 at one end of the arms 26. A transverse shaft 28 is mounted on the free ends of the arms 26, and mounted on the shaft 28 are sprockets (not shown) which mesh with teeth 30 annularly disposed around the interior surface of the wheels 20. The shaft 28 is driven by appropriate power transmission means interconnecting the shaft 28 and a power source located on the tractor 10 (not shown).

Additional support for the wheel 20 and buckets 22 assembly is provided by a second pair of arms 32 pivotally mounted on the tractor 10 at one end of the arms 32. A transverse block 34 is pivotally mounted on the free end-s of the arms 32, and the block34 has rollers 36 mounted thereon, the rollers 36 hearing on the interior surfaces of the Wheels 20 below the sprockets. A transverse arm 38 interconnects the block 34 and the shaft 28, while a second arm 40 is mounted on the block 34 and extends rearwar dly within the wheels 20. At the rear end of the arm 40 are rollers 42 which also bear on the interior surfaces of the wheels 20.

The assembly of the wheels 20 and the buckets 22 is elevated and lowered by means of a pair of hydraulic jacks 44 pivotally mounted on the tractor 10 and on the arms 26.

A pair of arms 50, preferably arcuate and substantially parallel to each other, are rigidly mounted at one end thereof to the arms 26 and extend rearwardly and downwardly therefrom. The arms 50 support a horizontally disposed frame structure 52, the frame structure 52 being disposed so as to partially surround the assembly of the wheels 20 and the buckets 22 and extend rearwardly therefrom. Radially disposed brackets 54, best shown in FIGS. 2 and 3, extend outwardly from the frame structure 52. Vertically disposed rollers 56 are mounted on the brackets 54 intermediate the ends of the brackets 54, and horizontally disposed rollers 58 are also mounted on the brackets 54, the rollers 58 being mounted closely adjacent to the rollers 56 and inwardly therefromtsee FIG. The rollers 58 have flanges 59 mounted on the upper ends thereof.

A conveyor ring 60 of suitable material, preferably metal, is provided. Mounted on the lower surface of the ring 60 intermediate the outer edges of the ring 60 is a continuous T-frame member 62 which has its crossarm positioned downwardly. The ring 60 and the T- frame member 62 are disposed so that the cross-arm of the T-frame member 62 will be seated on the vertically disposed rollers 56, the ring 60 being thus rotatably supported on the brackets 54, with the ring 60 surrounding the rear portion of the assembly of the wheel 20 and the buckets 22 in substantially horizontal position, the ring 60 being additionally disposed so that forwardly it is in position to receive dirt discharged from the buckets 22 between the wheels 20 as the assembly of the wheels 20 and the buckets 22 reaches the apex of its counterclockwise movement and commences its downward movement.

Mounted on the inward end of the cross-arm of the T-frame member 62 is a vertically oriented bearing ring 64, preferably of a sound-deadening material. The ring 64 is disposed so as to bear on the rollers 58 below the flanges 59, the rollers 58 thereby providing lateral support for the ring 60, and the flanges 59 serving to retain the ring 60 in its mounted position.

A friction-drive ring 66, also preferably of a sounddeadening material, is mounted externally on the leg of the T-frame member 62. A drive belt 68, again preferably of sound-deadening material, surrounds the friction-drive ring 66. The drive belt 68 is driven by a powered roller 70, shown in FIG. 3, the roller 70 being suitably mounted, as on the tractor 10, and being driven by power means (not shown). Slack in the drive belt 68 is eliminated by a suitably mounted and spring-biased roller 72. The ring 60 is thus powered to revolve in a clockwise direction.

It will be understood that in lieu of the friction drive for the ring 60 herein shown and described, other drive means, for such as chain-and-sprocket drive means, may be provided, but it has been found that the said friction drive means accomplishes its purpose with a lower noise level than is otherwise attained.

As best shown in FIGS. 4 and 6 of the drawings, upright brackets 80 are mounted on some of the radially disposed brackets 54. The brackets 80 are disposed adjacent the outer ends of the brackets 54, and they support a vertically oriented arcuate wall 82 which is disposed adjacent to the outer peripheral edge of the ring 60, and slightly above said outer peripheral edge, so that the wall 82 serves an outside retaining wall to keep dirt travelling on the conveyor ring 60 on the ring 60 and prevent the dirt from falling off the ring by centrifugal action. As illustrated in FIGS. 2 and 3, the Wall 82 does not completely surround the ring 60, but leaves a substantial portion of the outer peripheral edge of the ring 60 exposed as the ring 60 revolves.

A second vertically oriented arcuate wall 90 (see FIGS. 2 and 3) is suitably mounted on the brackets 54, the wall 90 being positioned adjacent to the inner edge of the ring 60 and slightly above said inner edge, over a substantial portion of the length of the wall 90, the wall serving as an inside retaining wall. One end 92 of the wall 90 is straightened. It tangentially crosses over the ring 60 beyond the adjacent terminal end of the wall 82, and terminates at an upright bracket 94 mounted adjacent the outer end of one of the brackets 54, this bracket 94 being one disposed in alignment with the trench line. The dispositions of the straight end 92 of the wall 90 and the adjacent terminal end of the wall 82 relative to each other are such that dirt carried on the ring 60 is discharged therebetween and directed in a discharge flow 96 toward the trench, in the manner hereinafter described and as shown in FIG. 1..

If desired, a baffle plate 98 may be mounted by any suitable means, as by a bracket 99, on the bracket 94 which supports the terminal end of the straight end 92 of the wall 90, the baffle plate 98 being disposed so as to direct the flow 96 toward the trench.

The other end 100 of the wall 90 is also straightened. It tangentially crosses over the ring 60 beyond the adjacent terminal end of the wall 82, and terminates at an upright bracket 102 mounted adjacent the outer end of one of the brackets 54, this bracket 54 being one disposed laterally on the device. The dispositions of the straight end 100 of the wall 90 and the adjacent terminal end of the wall 82 relative to each other are such that when it is desired to pile excavated dirt laterally of the trench, instead of refilling the trench automatically as the trencher progresses, the direction of travel of the ring 60 is reversed to a counterclockwise direction, and dirt carried on the ring 60 is then discharged between the two terminal ends of the walls 90 and 82 in a flow directed laterally of the trench.

A section of the wall 82 disposed on the opposite side of the device is separately pivotally mounted, as at 110, as illustrated in FIG. 3, so as to define a gate 112. The gate 112 is latched, as at 114, so that the gate 112 forms an integral part of the wall 82 when automatic trench refill is to be accomplished, but if it is desired to pile excavated dirt laterally of the trench on that side of the device, the gate 112 is unlatched and pivoted inwardly so that it is transversely disposed over the ring 60 in contact with the wall 90. With the ring 60 revolving in a clockwise direction, dirt travelling on the ring 60 will be diverted off the ring 60 by the gate 112, and will be discharged laterally of the device through the opening in the wall 82 thus provided.

If desired, an arcuate beam member 120, shown in FIGS. 1 and 4, may be provided. The beam (which is known in the industry as a crumber because its func tion is to break lumps of earth and smooth the bottom of the trench) is slidably mounted on the frame structure 52 in alignment with, but spaced apart from, the assembly of the wheels 20 and the buckets 22. A shoe 122 is mounted on the lower end of the beam 120 and disposed so as to ride along the bottom of the trench in back of the said wheels and buckets assembly. The beam 120 may be slidably raised and lowered by power means disposed in the frame structure 52 (not shown).

Means may be provided for directing a cable or conduit into the trench following the digging operation and before the automatic re-filling operation. As illustrated in the drawings, said means may comprise a somewhat S- shape pipe or conduit mounted on the frame structure 52 and disposed between the frame structure 52 and the ring 60, the upper end of the conduit 130 being disposed forwardly in the direction of the tractor 10 and above the wheels and buckets assembly. The lower end of the conduit 130 is bent rearwardly, and is disposed closely adjacent to the bottom of the trench. Stanchions are mounted on opposite sides of the tractor 10 adjacent the end of the tractor 10 opposite the end 14, and the stanchions 140 project outwardly and upwardly from the tractor 10. A cable reel 142 is rotatably and transversely mounted adjacent the free ends of the stanchions 140. A cable 144 is Wound on the reel 142. The

free end 145 of the cable144 is taken oil? the reel 142, passed over the tractor and through a guide block 146 mounted on a transverse shaft 148 disposed between the arms 26, is passed through the conduit 130, and placed on the bottom of the trench, as best shown in FIG. 1.

It will be understood that in lieu of the conduit 130, disposed as above described, other cable conducting means, such as a series of suitably supported pulleys, disposed, for instance, externally of the ring 60, may be provided.

In the alternative form of construction illustrated in FIG. 7, the ring 60, instead of being disposed in a flat horizontal plane, may be tilted upwardly and outwardly, with the walls 82 and 90 disposed substantially at right angles thereto. This alternative construction will overcome the tendency of the dirt carried by the ring 60 to pile up against the wall 82 when the ring 60 is revolving in a clockwise direction.

In operation, the tractor 10 is moved to straddle position over the proposed line of the trench to be dug, with the assembly of the wheels 20 and the buckets 22 of the digger unit elevated above the trench line. The digger unit is then lowered to the ground and powered, the assembly of the wheels and the buckets turning counterclockwise, as viewed in FIG. 1, to dig a trench as the tractor 10 proceeds to move to the right. The crumber 120 is also lowered, and as the desired trench depth is attained, the crumber 120 operates to smooth the bottom of the trench and assure a trench of substantially consistent depth through its entire length.

The free end 145 of the cable 144 is secured in the bottom of the trench behind the crumber 120 in any manner suitable to cause the cable 144 to unwind from the reel 142 as the tractor 10 continues to move to the right, it being understood that as the trench is re-filled in the manner hereinafter described, the trench fill itself will secure the cable 144 in the trench.

. As the tractor 10 continues to move to the right, and the digger unit continues to produce the trench, the cable 144 will. be continuously laid in the bottom of the trench.

Dirt removed from the trench will be carried upwardly in the buckets 22, and as the buckets reach the apex of their counterclockwise movement, the dirt will fall out of the buckets, will drop by gravity between the wheels 20, and will be continuously deposited on the ring 60, which has been powered to move in a clockwise direction when automatic trench re-fill is desired, and also when, in lieu of automatic trench re-fill, dirt deposit to the right of the trench, as viewed from the rear, is desired. If, in lieu of automatic re-fill, dirt deposit to the left of the trench is desired, the ring 60 will have been powered to move in a counterclockwise direction.

When automatic trench re-fill is to be accomplished, the gate 112 is latched in closed position, and the dirt deposited on the ring 60 moves clockwise With the ring 60 until it contacts the transverse straight end 92 of the Wall 90, whereupon it is directed off the ring 69 in discharge flow 96 to fill the trench over the cable 144.

Although not illustrated, if desired, water sprinkler means may be carried on the device so that, as the fill is deposited in the trench, water may be added to the fill to compact it. When, in lieu of automatic trench re-fill, it is desired to pile the excavated dirt laterally of the trench on the right side, the gate 112 is opened, and the dirt, moving clockwise with the ring 60, will contact the transversely positioned gate 112 and be directed off the ring 60 in a discharge flow on the right side of the trench. If, on the other hand, it is desired to pile the excavated dirt laterally of the trench on the left side, the ring 60 is revolved in a counterclockwise direction, and the dirt carried by the ring 60 will contact the transversely positioned straight end 100 of the wall 90 and be directed off the ring 60 in a discharge flow on the left side of the trench.

The clockwise and counterclockwise directional movements hereinabove described are given for ease of description and illustration, and are not to be deemed limiting to the basic concept of the invention, which can be accomplished by reversal of directional movements and corresponding reversal of elements.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiments thereof, it will be recognized that departures may be made therefrom within the scope of the invention, which is not limited to the details disclosed herein, but is to be accorded the full scope of the claims so as to embrace any and all equivalent structures and devices.

I claim:

1. In a trench digging and refilling apparatus adapted to be connected to a prime mover, the combination of; an endless trench digger unit having means for elevating the dirt to a point above ground level and discharging the dirt, a continuous and generally horizontal conveyor having its entire conveying surface facing upwardly with a portion of such surface passing laterally beneath the point of dirt discharge from said digger unit to receive such discharged dirt directly on said conveying surface, said horizontal conveyor extending both laterally and rearwardly of said digger unit to convey the dirt received from the digger unit, and selectively operable means associated with said horizontal conveyor for intercepting and selectively discharging the dirt from the conveyor into or laterally of the trench.

2. The apparatus of claim 1 wherein said horizontal conveyor is selectively operable to progress in either direction and said means for intercepting and selectively discharging the dirt include means at two separate locations along the conveyor and extending across the conveying surface which are separately operable upon operation of the conveyor in either direction for discharging the dirt into the trench in one direction of operation of the conveyor and laterally of the trench in the other direction of operation of the conveyor.

3. The apparatus of claim 1 wherein said trench digger unit includes an endless loop of means for elevating the dirt arranged with a lateral opening through the loop and said horizontal conveyor has the portion for receiving the discharged dirt passing through the loop opening.

4. The apparatus of claim 3 wherein said horizontal conveyor is comprised of a circular ring oriented in a substantially horizontal plane having the forward most portion passing through the loop opening of the digger unit and a rear most portion passing over the trench for discharging the dirt into the trench from said rear most portion. I

5. The apparatus of claim 4 wherein said horizontal conveyor ring is rotatable in either direction to move the dirt laterally in either direction and then rearwardly, and wall means extending diagonally across and immediately above the conveying surf-ace of said ring comprising the said means for intercepting and discharging the dirt from the conveyor, one said wall means positioned at the rear most portion of the conveyor for intercepting the dirt upon rotation of the conveyor in one direction and discharging the dirt into the trench and another said wall means at a lateral portion of the conveyor ring for intercepting the dirt upon rotation of the conveyor in the opposite direction to discharge the dirt laterally of the trench.

6. The apparatus of claim 5 including a third wall means selectively movable into and out of position for intercepting the dirt on the conveyor ring progressing toward the said rearwardly positioned wall means for diverting and discharging the dirt on that lateral side.

7. A trench digging device which comprises: a tractor unit; an endless digger unit mounted rearwardly on the tractor unit and disposed so as to continuously produce a trench as the tractor unit moves forwardly; drive means interconnecting the tractor unit and the digger unit for powering the digger unit; buckets mounted on the digger unit and disposed so as to elevate dirt removed from the trench and to discharge the dirt by gravity fiow at the apex of travel of the buckets; a substantially horizontally positioned conveyor ring supported on the digger unit and disposed so as to pass through the digger unit, and surround the rear portion of the digger unit and so as to receive the dirt discharged from the buckets and continuously convey the dirt rearwardly of the digger unit; drive means mounted on the conveyor ring for powering the conveyor ring; retaining walls mounted adjacent the conveyor ring and disposed so as to retain the dirt on the ring during conveyance; means disposed adjacent the rear of the conveyor ring for intercepting the dirt on the conveyor ring; and an opening in the retainer walls disposed so as to discharge the intercepted dirt rearwardly from the conveyor ring and deposit the dirt by gravity flow into the trench.

8. A trench digging device which comprises: a tractor unit; an endless digger unit mounted rearwardly on the tractor unit and disposed so as to continuously produce a trench as the tractor unit moves forwardly; drive means interconnecting the tractor unit and the digger unit for powering the digger unit; buckets mounted on the digger unit and disposed so as to elevate dirt removed from the trench and to discharge the dirt by gravity flow at the apex of travel of the buckets; a substantially horizontally positioned conveyor ring supported on the digger unit and disposed so as to pass through the digger unit, and

surround the rear portion of the digger unit and so as to receive the dirt discharged from the buckets and continuously convey the dirt rearwardly of the digger unit; drive means mounted on the conveyor ring for powering the conveyor ring; a first retaining wall mounted adjacent the outer peripheral edge of the conveyor ring, said first retaining wall terminating rearwardly so as to define a discharge opening therethrough; and a second retaining wall mounted adjacent the inner edge of the conveyor ring, said second retaining wall having a rearward terminal end transversely disposed over the conveyor ring so as to intercept the dirt conveyed by the conveyor ring in a first direction, divert the dirt through the discharge opening in the first retaining wall, and direct the dirt in a gravity flow into the trench.

9. A trench digging device which comprises: a tractor unit; an endless digger unit mounted rearwardly on the tractor unit and disposed so as to continuously produce a trench as the tractor unit moves forwardly; drive means interconnecting the tractor unit and the digger unit for powering the digger unit; buckets mounted on the digger unit and disposed so as to elevate dirt removed from the trench and to discharge the dirt by gravity flow at the apex of travel of the buckets; a substantially horizontally positioned conveyor ring supported on the digger unit and disposed so as to pass through the digger unit, and surround the rear portion of the digger unit and so as to receive the dirt discharged from the buckets and continuously convey the dirt rearwardly of the digger unit; drive means mounted on the conveyor ring for powering the conveyor ring; a first retaining wall mounted adjacent the outer peripheral edge of the conveyor ring, said first retaining Wall terminating rearwardly so as to define a discharge opening therethrough; and a second retaining wall mounted adjacent the inner edge of the conveyor ring, said second retaining wall having a rearward terminal end transversely disposed over the conveyor ring so as to intercept the dirt conveyed by the conveyor ring in a first direction, divert the dirt through the discharge opening in the first retaining wall, and direct the dirt in a gravity fiow into the trench; and said second retaining wall having a lateral terminal end transversely disposed over the conveyor ring so as to intercept the dirt conveyed by the conveyor ring in the opposite direction, divert the dirt through the discharge opening in the first retaining wall, and direct the dirt in a gravity flow laterally of the trench.

10. A trench digging device as defined in claim 9, including a gate pivotally mounted on the first retaining wall, said gate being disposed so as to swing transversely over the conveyor ring to intercept the dirt conveyed by the conveyor ring in the first direction, divert the dirt through the gate opening in the first retaining wall, and direct the dirt in a gravity flow laterally of the trench.

11. A trench digging device as defined in claim 10, including means for directing an elongate cable into the trench between the digger unit and dirt refill and continuously feeding said cable into the trench.

12. A trench digging device as defined in claim 11, wherein the means for directing and feeding the cable comprises an S-shaped conduit having its upper end disposed forwardly and having its lower end disposed rearwardly and closely adjacent to the bottom of the trench.

References Cited UNITED STATES PATENTS 1,584,591 5/1926 Arnold 3795 X 1,829,162 10/1931 Solter et al 61-72.6

3,203,188 8/1965 Evans 61--72.6

FOREIGN PATENTS 410,900 5/1934 Great Britain.

ERNEST R. PURSER, Primary Examiner. 

1. IN A TRENCH DIGGING AND REFILLING APPARATUS ADAPTED TO BE CONNECTED TO A PRIME MOVER, THE COMBINATION OF; AN ENDLESS TRENCH DIGGER UNIT HAVING MEANS FOR ELEVATING THE DIRT TO A POINT ABOVE GROUND LEVEL AND DISCHARGING THE DIRT, A CONTINUOUS AND GENERALLY HORIZONTAL CONVEYOR HAVING ITS ENTIRE CONVEYING SURFACE FACING UPWARDLY WITH A PORTION OF SUCH SURFACE PASSING LATERALLY BENEATH THE POINT OF DIRT DISCHARGE FROM SAID DIGGER UNIT TO RECEIVE SUCH DISCHARGED DIRT DIRECTLY ON SAID CONVEYING SURFACE, SAID HORIZONTAL CONVEYOR EXTENDING BOTH LATERALLY AND REARWARDLY OF SAID DIGGER UNIT TO CONVEY THE DIRT RECEIVED FROM 